Last



Oct; 26 1926.

w. A. KRKENTLER LAST Original Filed July 6. 1922 v 17111973' M4 M Patented Get. 26, 1926.

UNITED STATES 1,664,522 PATENT OFFICE.

WALTER A. KRENTLER, OF DETROIT, MICHIGAN, ASSIGNOR jTO IKRENTLER-ARNOLJD HINGE LAST COMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

LAST.

Application filed July 6, 1922, Serial No. 573,187. Renewed September 15, 1926.

My present invention is an improved last employing two parts, relatively movable, to shorten or lengthen the last, in combination with novel means for locking the last in either extreme position and for releasing the locking devices.

In the manufacture of shoes and lasts therefore it is important to have a shoe last which will afford great strength to resist the high speed and relatively heavy machines used under present modern shoe factory methods to withstand the bottoming operations, sole laying, heeling, etc. In many shoe factories it is customary to use solid lasts because ofthe breakage and other unsatisfactory working conditions found with two-part lasts, because the connecting and hinge constructions are unable either to withstand the above noted machine operations, or to maintain the last in locked extended position, as well as the difficulty of breaking the last to bend, flex or shorten it and withdraw it from the shoe. In order to produce a hinge last having the required strength and locking capacity to vithstand the bottoming strains and machine operations, it is necessary to have a very strong lock or spring and this requirement makes unlocking or breaking the last difficult, time consuming, and tiresome to the operator, furthermore, the use of separate levers or the like to effect the unlocking or releasing of the hinged last parts, requires an extra operation, extra expense and usually involves difficulty in holding the unlocking lever while flexing and shortening the last. A still further difficulty consists in structures which involve a cutting away of the wood of the last, thus reducing its strength, and yet where separate levers or the like were employed, this difficulty was present because of the necessity of the operator reaching into the shoe, to unlock the last, and hold the same released while flexing and withdrawing the last from the shoe.

All these difficulties above briefly mentioned, and others,have limited the use of hinge lasts, and in my present invention I have provided an improved last and hinge and locking construction therefor, as well as an unlocking construction which obviates the above difii'culties. Furthermore'in my I present invention I havedevised a structure permitting extremesimphcity of parts, economy of expense in assembling the same, and

have provided an automatically held unlocking member, so that the operator can simply touch or move the same and then leave the last unlocked and released during the subsequent flexing of the last and withdrawal does not require a cutting away of the last parts to any substantial extent, nor weakening of thewood of the last, and it is readily applicable to the improved hinge construction illustrated in my prior Patent 1,094,153, dated April 21, 1914-, and combines all the advantages of this type of last construction which has been well known in the trade as the standard 13. B. last.

In the present copending application of E. Of Krentler, No. 556,150, filed April 24E,

1922, is illustrated and claimed a somewhat similar construction, but in said'copending application, a specially formed sliding bolt was required to be employed, whereas in my present case I utilize and obtain the advantages of an ordinary hardened steel locking ball. My present construction acts to release the locking tension of this ball, to enable the releasing lever to be held in this unlocked condition while the operator removes tension therefrom, withdraws his hand and breaks and pulls the last from the shoe, whereas the completing ofthe flexing of the last automatically releases the unlocking lever and holds the last thus locked in broken or flexed position. I am enabled to utilize a stronger spring and se cure a greater locking tension, and also to employ a hardened steel ball, which is advantageous in the present construction.

Further features, advantages and details of construction will be hereinafter more fully pointed out and claimed.

Referring to the drawings, illustrating a preferred embodiment of my present inven a.

Fig. '1 shows my improved last locked in "exten'cled position, with a portion of the woodibrplgen away; i

Fig. 2 is a corresponding view on the line 2-2 of Fig. 1; and

Fig. 3 is a fragmentary view, illustrating the last in broken or flexed position, with the releasing lever free;

Fig. 4: being a fragmentary view of the action of the unlocking lever.

Referring to the drawings, the forepart 1 and heel part 2 are divided by a line of cut preferably to give to the abutting faces a knuckle joint construction, wherein the forepart 1 is formed with a concave face 3 and the heel part with a corresponding pro jecting knuckle or convex surface 41. This line of out furthermore terminates at the bottom face in the abutting faces 5 on the forepart and 6 on the heel part, and pro' vides a lock bearing against breaking ten sion during the bottoming operation.

In the forepart 1 is bored a suitable recess to receive the tubular hinge member 10 and in the rear part is also formed a saw cut or recess to receive the hinge plate 11. A rivet 12 holds the tube 10 firmly secured to the forepart and the rivet or pin 13 holds the plate 11 similarly secured to the heel part. A central pivot or pin 15 extends through the knuckle joint members, and through corresponding recesses in the tube 10 and plate 11, the tube 10 having its end portions slotted and formed as shown in Fig. 2, with the slotted ends 16, 16, spread outwardly, to permit the overlapping of the plate 11 for this purpose, as clearly shown in the drawings. This structure is utilized in the said patent above referred to, and present-simportant advantageous features which 1 am enabled to retain in my present construction. within the tube 10 is the lockin ball and spring 21. The plate 11 extends beyond 7 the pivot pin 15, presenting a nose or projection 25, and the concave face 26 coopcrating with the ball 20 to effect the locking of the last when the parts 1 and 2 are in either extended position as shown in Fig. 1, or in shortened position as shown in Fig. 2. The former position requires a locking contact of great strength, and therefore, as illustrated in Fig. 1, the concave surface 26 and nose produce a positive unbreakable locking action on the metal hinge members 11 and 12 and hence on the last parts 1. and 2. By forming the curved face 26 substantially in the manner as shown I secure the benefit of a constantly automatic and compensating locking means eliminating the danger of looseness from wear, the spring, locking ball, and curved face 26 always being in firm positive engagement irrespective of any Wear of the wood, pins, metal or looseness in these parts. This structure, combinedwith the knuckle joint, feature, affords great rigidity and is able to withstand torsional or other breaking strains in the Concealed, retained and protected.

last. In fact I so form these interlocking surfaces as to render the flexing of the last impossible, without first removing the ball 20 against the tension of the spring 21, the latter bearing against the ball and between the ball and the rivet 12 with an expansible action. Thus a positive, rigid, locking effeet is produced.

In order to release the positive lock as above explained, I have provided an unlocking member or lever, consisting in the handle port-ion 30 and a pair of extending wings or legs 31, 31, the latter straddling the plate 11 and being bored to receive the pivot pin 15 during the assembling of the last. These wings 31 also extend forwardly, sufficiently beyond the pivot pin 15 to present a pair of projecting noses 33, somewhat similar in contour to the projecting nose 25 on the plate 11, but of slightly shorter length, from the pivot pin 15 and of sufiiciently rounded contour so as to permit the forcing of the ball 20 out of its seat against the plate 11 and thus produce the releasing and unlocking of the last when the lever 30 is moved on the pivot 15 to the left viewing Figs. 1 and 2, as shown in Fig. 1.. Thus the forepart and heel part are released from the locking strain and tension, both of the spring 21 and the unbreakable locking surfaces afforded by the ball 20, concave face 26 and projecting nose portion 25, and the heel part can thereupon be freelymoved to shorten the last and remove it from the shoe. This permits great speed in the operation of pulling a last from the shoe, eliminates danger of straining the shoe upper during this action, greatly aids the operator and presents a most desirable feature in hinge last construction. The releasing lever is so formed as to be held in its releasing or unlocking action by the tension, of the ball 20 against the nose portions 33 of the locking lever until the movement of the last parts brings the nose 25 of the plate 11 again into contact with the ball 20, the latter being now held by the faces 33 to permit this action. Thereupon the nose 2' takes up the tension on the ball 20 and further compresses the spring 21, thereby automatically releasing the unlocking lever while transferring the tension of the spring 21 onto the heel part 2 and holding it locked in fiexed'or shortened position. In order to permit the full flexing of t e last parts of the \l-shaped faces 36 and 37 in contact, I may recess the forepart 1 slightly at 35, to house or conceal thelocking lever 30, but this inno way weakens the wood of the last. The heel recess for the plate 11 may also be enlarged slightly as shown at 40, in which the handle portion 30 may be partially housed, see Fig. 3. In the operation of my improved last constructi the parts 1 and 2,when mo ed, into lit) lengthened position, will be automatically locked by the engagement of the ball and cooperating locking faces on the plate 11. A slight rocking movement of the lever will instantly release this locking engagement and the lever 30 will be held in this position during the relative movement of the heel and forepart until the parts are moved so far that the nose 25 will take up contact with the ball 20 outside the face 26, the ball having been moved sufliciently to the left to permit this and the lesser diameter of the nose 33 compared with that of 25 on the same pivot 15 permitting this action. Thereupon the locking lever is instantly released and is automatically returned to normal position as shown in Fig. 1 upon the movement of the last parts in the opposite direction and the extending of the same as shown in Fig. 1. My present last, combining all the advantageous features of the tubular and plate metallic hinge members, locking ball and cooperating grooved faces on the plate 11 compensating automatically for looseness or wear, concealing all the locking parts, protecting the spring and ball, enabling the metal hinge members to be pinned in the solid wood of the last remote from the line of cut, the semi-automatic locking and unlocking of the releasing lever, combined with the knuckle joint structure, and the economy 01 construction, assembling and great strength, produce a most desirable last of this type.

My invention is further described and defined in the form of claims as follows:

i. A hinge last of the kind described, having a heel part and a forepart pivotally connected for relative movement, means for positively locking the last parts in extended position, and means for releasing said locking means, to permit shortening of the last, in combination with means to release said releasing means from its releasing position during the completion of the last shortening operation.

2. A hinge last of the kind described, having a heel part and a forepart connected for relative movement, means for positively locking the last parts in extended position, and means for releasing said locking means, to permit shortening of the last, in combination with means to release said releasing means from its releasing position during the completion of the last shortening oper-- ation, whereby said last parts are positively locked in extended position and yieldingly locked in shortened position.

I 3. A two-part last, having means to connect said last parts, and permit relative move ment for lengthening and shortening, a locking element to hold the last parts in ex tended position, an unlocking element to release said locking element from its locking tension, and means permitting the subsequent releasing of the unlocking element from its releasing position during the relative movement of the forepart and heel part.

a. A two-part last having hinge members, one member being of tubular form and secured to one part, the other member'being a plate and secured to the other part, a pivotpin uniting said members, locking means carried by one member, and look releasing means carried by the other member, said lock releasing means being constructed and arranged to afford a manual movement releasing the locking means and then being itself locked in its lock releasing position to permit free flexing of the last parts.

5. A two-part last, having a heel part and forepart arranged for relative movement, a tubular hinge member in one part, a plate member in the other part, a pivotal pin uniting said hinge members, locking means carried by the tubular member, a spring to move said lockingmeans into looking engagement with the plate and tubular member to afford a positive rigid lock, an unlocking lever straddling the plate member and held in assembled position by the pivot pin of the last, said unlocking lever having a handle portion and an extending portion to remove said locking member against the tension of its spring to permit free unlocking of the last.

I 6. A two-part last, having a heel part and forepart arranged for relative movement, a

tubular hinge member in one part, a plate,

member in the other part, a pivot pin uniting said hinge members, a locking ball carried by the tubular member, a spring to move said locking ball into looking engagement with the plate and tubular member to afford a positive rigid lock, an unlocking lever straddling the plate member and held in assembled position by the pivot pin of the last, said unlocking lever having a handle portion and a plurality of ball engaging portions to remove said locking ball against the tension of its spring and permit free unlocking of the last.

In testimony whereof I have signed my name to this specification. 

